DVDs become common as optical discs onto which various information such as main-video information, audio information, sub-video information, reproduction control information and so on is recorded. According to a DVD standard, the main-video information (video data), the audio information (audio data) and the sub-video information (sub-picture data) are packetized each with the reproduction control information (navigation data) and multi-recorded onto a disc in a program stream format of MPEG 2 (Moving Picture Experts Group phase 2), which is a high performance encoding technology. Among them, the main-video information has data, which is compressed in a MPEG video format (ISO 13818-2), for one stream in one program stream. On the other hand, the audio information is recorded in a plurality of formats (i.e. linear PCM, AC-3, MPEG audio and so on) and has data for up to 8 streams in one program stream. The sub-video information is defined by a bitmap, and is compressed and recorded in a run length method, and has data for up to 32 streams in one program stream.
On the other hand, a transport stream of MPEG2 standard is coming to be standardized, which is suitable for data transfer. According to the transport stream format, a plurality of elementary streams is transferred at the same time. For example, a plurality of programs, such as a plurality of satellite digital broadcasting channels in one satellite radio wave, is transmitted at the same time in a TDM (Time Division Multiplex) scheme.
In DVD's of this type, sub-picture information as the sub-video information to indicate the sub-video such as a caption for a movie may be recorded, in association with video information as the main-video information. When a DVD of this type is reproduced, the sub-picture may be displayed over the video or the main-picture. For example, an English caption as the sub-picture may be superimposed over the video screen of the movie. Instead of this, a Japanese caption as the sub-picture may be superimposed.
For example, as the information to control displaying such a sub-picture, there are recorded information to indicate a display area of sub-picture pixel data in a video display area; information to designate a position of the sub-picture pixel data in the display area; scroll information to scroll the sub-picture from side to side or up and down relative to the display area; and so on. As a relatively complex and sophisticated sub-picture display, the caption for the movie can be scrolled with the aid of the scroll information.